What size belly button ring should I wear, if the standard 3/8" barbell is too long or short? If you have a shallow piercing, and the 3/8" curved barbell is too long, then you should wear a 5/16" length.

If you have a Deep piercing, and the 3/8" curved barbell is too short, you should wear a 1/2" long barbell. If this is still too tight, then you will need a 5/8" long barbell.